Pang repair log

Going through some PCBs I've bought recently in a lot.

Here's on the bench an original Pang PCB :

 

At closer inspection I noticed the suicide battery was recently replaced and still with charge so I powered the board up.The board booted up and played fine but colors were wrong, screen was blueish (this denotes troubles with red ) :

Upon a quick look at the board I located the palette RAMs, two Sony CK5814 (quite unreliable part in my experience) :

Probing the one @8C revealed all the eight data pins stuck high (while the address lines were toggling)

Sure enough I removed the chip:

And tested it in my Retro Chip Tester (great device, highly recommended!), it failed :

 I fitted a round machined socket and a good RAM chip :

This restored correct colors.Another board 100% fixed.

 

Spider-Man (conversion on Sega System32 hardware) repair log

I got for repair a clean Spider-Man PCB set, actually a conversion on a donor Sega System 32 ROM board (motherboard was from Rad Rally) :

The board booted up and played fine but sound samples (FXs, speeches, etc...) were totally missing :

Looking at hardware the samples are handled by a surface mounted IC marked 'ASSP 5C105' :

The chip is actually a 'RF5C68A'in disguise, a PCM sound generator IC manufactured by Ricoh and used in Fujitsu's FM Towns computer series, along with Sega's System 18 /32 arcade system (sometimes you can find it marked as 'ASSP 5C68A' and Sega '315-5476').Datasheet is available so I looked at  the pinout :

Pin 36 'SDLH' is the serial data output connected to pin 8 of the near Sanyo LC7881 DAC (for digital to analog conversion), probing this pin I found it stuck low all the time :

This was a clear sign the 'ASSP 5C105' was internally fault.Sure enough I removed it with my hot air station :

 

I took a spare from a dead System32 motherboad and installed it :

 This restored all sound samples and fixed board completely.Job done.